Jim Haskin and Amy Husten fell in love fast, and within four months of meeting in late 1999, they were looking for a house together. They were both artists with busy professional lives in separate cities: She is a ceramicist and a project director for the department that looks into overseas ventures for the Guggenheim Museum; he paints portraits and is a partner at R&F Handmade Paints, a fine-art paint company in Kingston, N.Y. If their relationship was to work, they reasoned, they needed a home base.

But there was a problem: Husten liked stone farmhouses, and to Haskin, that meant small rooms and low ceilings, which held no appeal for him. "I'm claustrophobic," he explained.

A year of frustrating house hunting later, they stumbled on a solution when Haskin mentioned that he was a fan of the California Case Study houses. The homes, built in and around Los Angeles after World War II by architects and designers like Eero Saarinen, Richard Neutra, and Charles and Ray Eames, were part of a program aimed at producing low-cost, experimental modern housing. Although they were antithetical in style to an old-fashioned farmhouse, Husten liked them, too. She and Haskin decided they could build an experimental, light-filled and relatively cheap house of their own in the Catskills, and over the past five years, on a budget of $500,000, they did.

The couple started with 2 acres of heavily wooded, hilly land in Stone Ridge -- once part of a cow pasture -- which they bought for $36,000 in 2000. Then they spent months poring over books on Case Study houses and interviewing architects, most of whom were too expensive. Finally, in late 2001, they met Erin Vali, a young architect -- he had just turned 30 -- who was about to open his own firm, Ulterior Mode in Brooklyn, and was willing to work cheap. He had never built a freestanding structure, but the couple felt an instant affinity for both his low-key personality and the apartment renovations in his portfolio.

"He would transform a boring space into an interesting home by inserting a floating staircase, a balcony overlooking the main floor, and he would maximize light and storage," Husten said. "He leaves no space unused."

The two-story house that resulted is 1,800 square feet, and the adjoining two-story art studio, with work spaces for both Haskin and Husten, is 900. It was a big change for both of them: Until 2004, Husten, now 50, lived in a 500-square-foot studio on the Upper West Side; Haskin, now 44, had an equally small one-bedroom apartment in Kingston.

Vali pointed out that the cost of the house and the adjoining studios -- $185 per square foot including land -- is less than the cost of many prefabricated homes on the market. (Most prefabricated houses cost $150 to $250 a square foot, excluding land, according to Allison Arieff, the editor of Dwell magazine and a co-author of the book "Prefab.")

The main challenge to keeping costs down, Vali said, was the exterior cladding. Most builders use two layers of materials to clad a house -- plywood and a weatherproof material like wood shingles or brick veneer -- which can be expensive. Vali had a hunch that a single layer of T-111, a Douglas fir plywood often used for sheds and barns, would protect much of the house and studio from the elements, and his contractor agreed. They had the top halves of both buildings covered with the material, arranged in vertical slats in the style of a barn wall. Some of the bottom halves of the buildings have a plywood underlayer and a top layer of cement board, a composite of cement and glass fiber that is typically used under tile in bathrooms and kitchens and is much cheaper than the usual outer layer of cladding. Vali had the material cut into 2-by-4-foot boards and mounted them horizontally, so that they overlapped slightly, like shingles. He had used cement board before for interior walls, and knew that it would take paint, which would help protect it from moisture.

Inside, Husten and Haskin opted for a 14-foot ceiling and a simple open plan for the first floor of the house, in keeping with Haskin's taste for open spaces. Most of the floor is given over to a living-dining-kitchen area, which is furnished with dining chairs from Ikea and a dining table and a sectional sofa from Bo Concept in Manhattan, another store that sells low-priced Scandinavian furniture. The kitchen is free of status appliances: The couple entertain a lot -- friends and family -- and said they were happy with a KitchenAid stove and a General Electric refrigerator.

Compensating for the plainness of the interior, Vali and his clients chose a wild palette for the walls and the furnishings.

"Jim manufactures artists' paints, and he's attracted to bold color as a painter," Husten said. "We looked at a gazillion chips, and were looking for families of colors that would go together."

The sofas are mostly purple. The kitchen is red, Husten's favorite color. The fireplace wall is an acid green, and the wall by the staircase is yellow. They used Vali's Photoshop computer program to try dozens of combinations for the exterior walls -- orange and pale orange, orange and turquoise, shocking pink and lavender -- before settling on colors inspired by the surrounding foliage: the yellow of autumn birch leaves for the cement board, the red of turning maple for the T-111.

Tucked behind the staircase, whose maple treads extend to become shelves for a bookcase in the living area, are a guest room, a bathroom and a television room. Upstairs, in addition to the master bedroom and a second bathroom, Vali had designed a home office intended to open directly onto a balcony overlooking the living-dining area. But in 2003, just as construction began, he had to rethink that room after Husten became pregnant with Harry, who is now 2.

"He was a big surprise," said Husten, who was 47 at the time.

The office became Harry's bedroom, and for about $1,000, Vali was able to close it off with a sliding door and a translucent wall.

Light pours into the house through two skylights and many oversize 4-foot-high windows on all sides. Upstairs, an exterior door opens onto a terrace with a 180-degree view of the Catskills. From here, Haskin can get to his second-floor studio, which is above his wife's, by means of an outdoor catwalk; the two studios are not connected within.

"We needed separate studios. Clay is very dusty," Haskin said, referring to his wife's work as a ceramicist.

Husten and Haskin spent extravagantly on just a few items in the project: the stained maple bookcase-stair unit at $35,000; the radiant-heated concrete slab flooring on the first floor, which cost $15 a square foot and allows the family to go barefoot even in the winter; and a first-floor bathroom tiled in a custom pattern of blue, green, teal, red and white, which was $16 a square foot including installation. "A vague takeoff on Bilbao," Husten said, referring to the Guggenheim Museum's bathrooms in Bilbao, Spain, which are tiled in a similar pattern in brown, orange, yellow, mustard and white.

"There are a few things you can splurge on that add more value than they actually cost," Haskin said. "Warm feet -- you can't put a value on that, especially when you live in the Northeast. And the bathroom is about private time, something you appreciate even more with a 2-year-old."